8 Responses. > 1  the Moon takes an elliptical path around the Earth. The planets make nearly elliptical orbits around the Sun, close enough for reasonable approximations, but the Moonâs Orbit around the Earth is sufficiently influenced by the Sun that it follows a path detectably different from an ellipse.
Quick Answer. In 1896, French scientist Antoine Henri Becquerel discovered radioactivity which was an early contribution to atomic theory. He discovered this phenomenon while experimenting with uranium and a photographic plate. Continue Reading.
A Pattern of properties appeared when he arranged the elements in order of increasing atomic mass.mitri Mendeleev discovered scandium, gallium, technetium, and  germanium. He also predicted the existence of more elements and  developed the modern periodic table.